Construction on Gilbert Street Bridge to begin in late April

Complete closure of thoroughfare will lead to detours

Feb. 10, 2023 6:00 am

IOWA CITY — Drivers and pedestrians should expect detours this spring when the heavily traveled Gilbert Street Bridge near downtown Iowa City is replaced.

The four-lane concrete bridge over Ralston Creek will be removed and replaced with a new four-lane design that meets local and state guidelines for traffic and pedestrians. There will be 6-foot sidewalks on both sides, as well as aesthetic improvements to enhance the neighborhood and offer views of the creek.

Water main improvements will occur north of the bridge, and overhead utilities in the project area will be moved underground.

This portion of Gilbert Street will be closed for about five months as the bridge is being replaced. Construction on the $2.9 million project is expected to begin in late April and wrap up in early October, with incentives if the contractor finishes early.

The Iowa City Council this week approved project details and estimated cost of construction.

“The timeline and speed of this project is going to be really important because of the nature of this thoroughfare,” council member Shawn Harmsen said during the Tuesday meeting.

Inspection by the Iowa Department of Transportation and city over the years identified the bridge as needing to be replaced. The current bridge was constructed in 1972.

There is advanced deterioration of the bridge deck and super structure, as well as “significant cracking and spalling” that requires frequent maintenance, according to a city memo. It was also noted there is widespread minor damage and also no barrier separating pedestrians from vehicles.

The city received grant funding from the Iowa DOT of up to $1 million for the project. The city will cover remaining costs with bond financing, said Melissa Clow, special projects administrator.

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The state will bid the project in March. City staff will go to the Iowa City Council in early April with a contractor recommendation for the council to consider. Construction would begin later that month.

The contractor will have 170 calendar days to complete the work necessary to open the street to through traffic, Clow said. This will require a six-day workweek, with the option to work Sundays.

The contractor can receive an additional $4,000 per day for completing the work early with a maximum incentive of $40,000, Clow said. For every day the road is closed beyond the 170 days, there is a penalty of $4,000 per day.

The project will be broken up into phases, Clow said. The first phase will be preparing for road closure since a complete closure of Gilbert Street will be needed. City staff will have one to two weeks before construction begins to start putting up detour signs, Clow said.

Council members this week highlighted how it will be important to communicate the detours to the public with this being one of the city’s main thoroughfares. The city typically communicates information about road projects and closures through its website and social media accounts.

“I think we’ve leaned some good lessons last year about how we communicate about road closures,” council member Laura Bergus said. “I would imagine that we’re going to be really aggressive in letting people know that one of our main thoroughfares will be closed for a number of months and if the schedule changes we’ll let them know as soon as possible.”

A project map shows drivers should use S. Dubuque Street as a detour. Pedestrians should use S. Linn Street as a detour.

Gilbert Street Bridge Replacement Project Traffic Control Map by Gazetteonline on Scribd

There will be accommodations for parking and access to businesses during construction, Clow said.

“We'll be constructing a temporary driveway at the parking lot on the north side of the bridge to access Maiden Lane so that traffic can still get down Gilbert to access businesses and then get out onto Maiden Lane,” Clow said.

The second and third phases will be construction of storm sewer and the bridge. For phase four, once the road is open, the storm sewer at the Court Street intersection will be completed.

Comments: (319) 339-3155; [email protected]